* [PATCH v2] certs: Add EFI_CERT_X509_GUID support for dbx entries
@ 2020-09-09 17:27 Eric Snowberg
2020-09-09 17:40 ` Randy Dunlap
[not found] ` <20200914180127.GA9369@linux.intel.com>
0 siblings, 2 replies; 4+ messages in thread
From: Eric Snowberg @ 2020-09-09 17:27 UTC (permalink / raw)
To: dhowells, dwmw2, jarkko.sakkinen
Cc: herbert, davem, jmorris, serge, nayna, zohar, eric.snowberg,
erichte, mpe, keyrings, linux-kernel, linux-crypto,
linux-security-module
The Secure Boot Forbidden Signature Database, dbx, contains a list of now
revoked signatures and keys previously approved to boot with UEFI Secure
Boot enabled. The dbx is capable of containing any number of
EFI_CERT_X509_SHA256_GUID, EFI_CERT_SHA256_GUID, and EFI_CERT_X509_GUID
entries.
Currently when EFI_CERT_X509_GUID are contained in the dbx, the entries are
skipped.
Add support for EFI_CERT_X509_GUID dbx entries. When a EFI_CERT_X509_GUID
is found, it is added as an asymmetrical key to the .blacklist keyring.
Anytime the .platform keyring is used, the keys in the .blacklist keyring
are referenced, if a matching key is found, the key will be rejected.
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
---
v2:
Fixed build issue reported by kernel test robot <lkp@intel.com>
Commit message update (suggested by Jarkko Sakkinen)
---
certs/blacklist.c | 36 +++++++++++++++++++
certs/system_keyring.c | 6 ++++
include/crypto/pkcs7.h | 8 +++++
include/keys/system_keyring.h | 11 ++++++
.../platform_certs/keyring_handler.c | 11 ++++++
5 files changed, 72 insertions(+)
diff --git a/certs/blacklist.c b/certs/blacklist.c
index 6514f9ebc943..17ebf50cf0ae 100644
--- a/certs/blacklist.c
+++ b/certs/blacklist.c
@@ -15,6 +15,7 @@
#include <linux/err.h>
#include <linux/seq_file.h>
#include <keys/system_keyring.h>
+#include <crypto/pkcs7.h>
#include "blacklist.h"
static struct key *blacklist_keyring;
@@ -100,6 +101,41 @@ int mark_hash_blacklisted(const char *hash)
return 0;
}
+int mark_key_revocationlisted(const char *data, size_t size)
+{
+ key_ref_t key;
+
+ key = key_create_or_update(make_key_ref(blacklist_keyring, true),
+ "asymmetric",
+ NULL,
+ data,
+ size,
+ ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW),
+ KEY_ALLOC_NOT_IN_QUOTA |
+ KEY_ALLOC_BUILT_IN);
+
+ if (IS_ERR(key)) {
+ pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key));
+ return PTR_ERR(key);
+ }
+
+ return 0;
+}
+
+int is_key_revocationlisted(struct pkcs7_message *pkcs7)
+{
+ int ret;
+
+ ret = pkcs7_validate_trust(pkcs7, blacklist_keyring);
+
+ if (ret == 0)
+ return -EKEYREJECTED;
+
+ return -ENOKEY;
+}
+EXPORT_SYMBOL_GPL(is_key_revocationlisted);
+
/**
* is_hash_blacklisted - Determine if a hash is blacklisted
* @hash: The hash to be checked as a binary blob
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 798291177186..f8ea96219155 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -241,6 +241,12 @@ int verify_pkcs7_message_sig(const void *data, size_t len,
pr_devel("PKCS#7 platform keyring is not available\n");
goto error;
}
+
+ ret = is_key_revocationlisted(pkcs7);
+ if (ret != -ENOKEY) {
+ pr_devel("PKCS#7 platform key revocationlisted\n");
+ goto error;
+ }
}
ret = pkcs7_validate_trust(pkcs7, trusted_keys);
if (ret < 0) {
diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h
index 38ec7f5f9041..d8f2e0fdfbf4 100644
--- a/include/crypto/pkcs7.h
+++ b/include/crypto/pkcs7.h
@@ -26,11 +26,19 @@ extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
const void **_data, size_t *_datalen,
size_t *_headerlen);
+#ifdef CONFIG_PKCS7_MESSAGE_PARSER
/*
* pkcs7_trust.c
*/
extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
struct key *trust_keyring);
+#else
+static inline int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
+ struct key *trust_keyring)
+{
+ return -ENOKEY;
+}
+#endif
/*
* pkcs7_verify.c
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index fb8b07daa9d1..b6991cfe1b6d 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -31,11 +31,14 @@ extern int restrict_link_by_builtin_and_secondary_trusted(
#define restrict_link_by_builtin_and_secondary_trusted restrict_link_by_builtin_trusted
#endif
+extern struct pkcs7_message *pkcs7;
#ifdef CONFIG_SYSTEM_BLACKLIST_KEYRING
extern int mark_hash_blacklisted(const char *hash);
+extern int mark_key_revocationlisted(const char *data, size_t size);
extern int is_hash_blacklisted(const u8 *hash, size_t hash_len,
const char *type);
extern int is_binary_blacklisted(const u8 *hash, size_t hash_len);
+extern int is_key_revocationlisted(struct pkcs7_message *pkcs7);
#else
static inline int is_hash_blacklisted(const u8 *hash, size_t hash_len,
const char *type)
@@ -47,6 +50,14 @@ static inline int is_binary_blacklisted(const u8 *hash, size_t hash_len)
{
return 0;
}
+static inline int mark_key_revocationlisted(const char *data, size_t size)
+{
+ return 0;
+}
+static inline int is_key_revocationlisted(struct pkcs7_message *pkcs7)
+{
+ return -ENOKEY;
+}
#endif
#ifdef CONFIG_IMA_BLACKLIST_KEYRING
diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c
index c5ba695c10e3..cc5a43804bc4 100644
--- a/security/integrity/platform_certs/keyring_handler.c
+++ b/security/integrity/platform_certs/keyring_handler.c
@@ -55,6 +55,15 @@ static __init void uefi_blacklist_binary(const char *source,
uefi_blacklist_hash(source, data, len, "bin:", 4);
}
+/*
+ * Revocationlist the X509 cert
+ */
+static __init void uefi_revocationlist_x509(const char *source,
+ const void *data, size_t len)
+{
+ mark_key_revocationlisted(data, len);
+}
+
/*
* Return the appropriate handler for particular signature list types found in
* the UEFI db and MokListRT tables.
@@ -76,5 +85,7 @@ __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type)
return uefi_blacklist_x509_tbs;
if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
return uefi_blacklist_binary;
+ if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
+ return uefi_revocationlist_x509;
return 0;
}
--
2.18.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] certs: Add EFI_CERT_X509_GUID support for dbx entries
2020-09-09 17:27 [PATCH v2] certs: Add EFI_CERT_X509_GUID support for dbx entries Eric Snowberg
@ 2020-09-09 17:40 ` Randy Dunlap
2020-09-09 22:44 ` Eric Snowberg
[not found] ` <20200914180127.GA9369@linux.intel.com>
1 sibling, 1 reply; 4+ messages in thread
From: Randy Dunlap @ 2020-09-09 17:40 UTC (permalink / raw)
To: Eric Snowberg, dhowells, dwmw2, jarkko.sakkinen
Cc: herbert, davem, jmorris, serge, nayna, zohar, erichte, mpe,
keyrings, linux-kernel, linux-crypto, linux-security-module
On 9/9/20 10:27 AM, Eric Snowberg wrote:
> diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h
> index 38ec7f5f9041..d8f2e0fdfbf4 100644
> --- a/include/crypto/pkcs7.h
> +++ b/include/crypto/pkcs7.h
> @@ -26,11 +26,19 @@ extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
> const void **_data, size_t *_datalen,
> size_t *_headerlen);
>
> +#ifdef CONFIG_PKCS7_MESSAGE_PARSER
> /*
> * pkcs7_trust.c
> */
> extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
> struct key *trust_keyring);
> +#else
> +static inline int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
> + struct key *trust_keyring)
> +{
> + return -ENOKEY;
> +}
> +#endif
Just to be clear, you want to do the #else block when
CONFIG_PKCS7_MESSAGE_PARSER=m. Is that correct?
If so, it might be clearer to use
#if IS_BUILTIN(CONFIG_PKCS7_MESSAGE_PARSER)
--
~Randy
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] certs: Add EFI_CERT_X509_GUID support for dbx entries
2020-09-09 17:40 ` Randy Dunlap
@ 2020-09-09 22:44 ` Eric Snowberg
0 siblings, 0 replies; 4+ messages in thread
From: Eric Snowberg @ 2020-09-09 22:44 UTC (permalink / raw)
To: Randy Dunlap
Cc: dhowells, dwmw2, Jarkko Sakkinen, herbert, davem, jmorris, serge,
nayna, Mimi Zohar, erichte, mpe, keyrings, linux-kernel,
linux-crypto, linux-security-module
> On Sep 9, 2020, at 11:40 AM, Randy Dunlap <rdunlap@infradead.org> wrote:
>
> On 9/9/20 10:27 AM, Eric Snowberg wrote:
>> diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h
>> index 38ec7f5f9041..d8f2e0fdfbf4 100644
>> --- a/include/crypto/pkcs7.h
>> +++ b/include/crypto/pkcs7.h
>> @@ -26,11 +26,19 @@ extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
>> const void **_data, size_t *_datalen,
>> size_t *_headerlen);
>>
>> +#ifdef CONFIG_PKCS7_MESSAGE_PARSER
>> /*
>> * pkcs7_trust.c
>> */
>> extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
>> struct key *trust_keyring);
>> +#else
>> +static inline int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
>> + struct key *trust_keyring)
>> +{
>> + return -ENOKEY;
>> +}
>> +#endif
>
> Just to be clear, you want to do the #else block when
> CONFIG_PKCS7_MESSAGE_PARSER=m. Is that correct?
>
> If so, it might be clearer to use
>
> #if IS_BUILTIN(CONFIG_PKCS7_MESSAGE_PARSER)
>
I just added this part to fix a build error when none of the
asymmetrical keys are defined within a config. I failed to notice
CONFIG_PKCS7_MESSAGE_PARSER could be configured to build as a module
too. The code I added that uses pkcs7_validate_trust is always
builtin. Taking this into account, please disregard this patch.
I will need to solve this a different way. Thanks for pointing this
out.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] certs: Add EFI_CERT_X509_GUID support for dbx entries
[not found] ` <20200914180127.GA9369@linux.intel.com>
@ 2020-09-14 18:02 ` Jarkko Sakkinen
0 siblings, 0 replies; 4+ messages in thread
From: Jarkko Sakkinen @ 2020-09-14 18:02 UTC (permalink / raw)
To: Eric Snowberg
Cc: dhowells, dwmw2, herbert, davem, jmorris, serge, nayna, zohar,
erichte, mpe, keyrings, linux-kernel, linux-crypto,
linux-security-module
On Mon, Sep 14, 2020 at 09:01:34PM +0300, Jarkko Sakkinen wrote:
> On Wed, Sep 09, 2020 at 01:27:36PM -0400, Eric Snowberg wrote:
> > The Secure Boot Forbidden Signature Database, dbx, contains a list of now
> > revoked signatures and keys previously approved to boot with UEFI Secure
> > Boot enabled. The dbx is capable of containing any number of
> > EFI_CERT_X509_SHA256_GUID, EFI_CERT_SHA256_GUID, and EFI_CERT_X509_GUID
> > entries.
> >
> > Currently when EFI_CERT_X509_GUID are contained in the dbx, the entries are
> > skipped.
> >
> > Add support for EFI_CERT_X509_GUID dbx entries. When a EFI_CERT_X509_GUID
> > is found, it is added as an asymmetrical key to the .blacklist keyring.
> > Anytime the .platform keyring is used, the keys in the .blacklist keyring
> > are referenced, if a matching key is found, the key will be rejected.
> >
> > Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
> > ---
> >
> > v2:
> > Fixed build issue reported by kernel test robot <lkp@intel.com>
> > Commit message update (suggested by Jarkko Sakkinen)
> >
> > ---
> > certs/blacklist.c | 36 +++++++++++++++++++
> > certs/system_keyring.c | 6 ++++
> > include/crypto/pkcs7.h | 8 +++++
> > include/keys/system_keyring.h | 11 ++++++
> > .../platform_certs/keyring_handler.c | 11 ++++++
> > 5 files changed, 72 insertions(+)
> >
> > diff --git a/certs/blacklist.c b/certs/blacklist.c
> > index 6514f9ebc943..17ebf50cf0ae 100644
> > --- a/certs/blacklist.c
> > +++ b/certs/blacklist.c
> > @@ -15,6 +15,7 @@
> > #include <linux/err.h>
> > #include <linux/seq_file.h>
> > #include <keys/system_keyring.h>
> > +#include <crypto/pkcs7.h>
> > #include "blacklist.h"
> >
> > static struct key *blacklist_keyring;
> > @@ -100,6 +101,41 @@ int mark_hash_blacklisted(const char *hash)
> > return 0;
> > }
> >
> > +int mark_key_revocationlisted(const char *data, size_t size)
> > +{
> > + key_ref_t key;
> > +
> > + key = key_create_or_update(make_key_ref(blacklist_keyring, true),
> > + "asymmetric",
> > + NULL,
> > + data,
> > + size,
> > + ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
> > + KEY_USR_VIEW),
> > + KEY_ALLOC_NOT_IN_QUOTA |
> > + KEY_ALLOC_BUILT_IN);
> > +
> > + if (IS_ERR(key)) {
> > + pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key));
> > + return PTR_ERR(key);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +int is_key_revocationlisted(struct pkcs7_message *pkcs7)
> > +{
> > + int ret;
> > +
> > + ret = pkcs7_validate_trust(pkcs7, blacklist_keyring);
> > +
> > + if (ret == 0)
> > + return -EKEYREJECTED;
> > +
> > + return -ENOKEY;
> > +}
> > +EXPORT_SYMBOL_GPL(is_key_revocationlisted);
>
> What required this callable from a module?
Right, nees to be exported for pkcs7.
/Jarkko
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-09-09 17:27 [PATCH v2] certs: Add EFI_CERT_X509_GUID support for dbx entries Eric Snowberg
2020-09-09 17:40 ` Randy Dunlap
2020-09-09 22:44 ` Eric Snowberg
[not found] ` <20200914180127.GA9369@linux.intel.com>
2020-09-14 18:02 ` Jarkko Sakkinen
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